Traditional rights management of physical materials benefits from the physical nature of the material being protected, as this provides some limitation to the ease with which this content can be copied or otherwise stolen. Digital files, however, can be very easily copied, and already copyright violations are widespread, as for example illegal downloading of music files. Digital rights management (DRM) technology addresses the need to identify, protect, monitor, and track digital materials and their use.
Several DRM protocols or standards have emerged to support secure, authorized access to digital materials including extensible rights markup language (XrML), open digital rights language (ODRL), a Sony proprietary content management protocol, and an Apple Computer proprietary content management protocol, just to name a few.
DRM protocols permit a device to download a digital file from a content provider and to access this file, for example a digital music file, a fixed number of times within a fixed time window in exchange for charging a fee to a credit card or to an account with the content provider. For example, an individual might download a song performed by a popular artist to an Internet enabled audio system for five plays over the next seven days.